This application relates generally to disc drive data storage devices and more particularly to a shock limiting suspension for a magnetic read/write transducer in a disc drive.
Typically a gimbal assembly at one end of an elongated flexure sometimes called a load beam or suspension member supports the head over the data disc in a disc drive. The other end of the flexure or load beam is securely fastened, usually by staking, to a distal end of an actuator arm that is rotatably positioned adjacent the disc or stack of discs in the disc drive. Suspension limiters are used in those disc drives designed to park the read/write transducers or heads off of the discs on a shelf or ramp when the drive is typically either in a power saving mode or deenergized. The suspension limiter functions to help lift the head from the disc during head unload to the ramp and to prevent excessive strain on the gimbal during unload and prevent excessive strain if the drive is subjected to a shock load while the drive is deenergized or in a power save mode and the heads are positioned off of the disc. The end of the flexure carrying the head is suspended by a tab extending from the free end of the flexure into a slot formed in the parking ramp.
The head is supported by a gimbal attached to the load beam that permits the head to pitch, roll and yaw about the pivot point on the gimbal. The gimbal, in turn, is suspended from the load beam. When a shock load is applied to the deenergized drive, the head tends to move away from its supporting gimbal. A shock limiter is typically an extension tab on the gimbal which, when the drive is placed under a predetermined external shock load, engages a portion of the flexure or load beam to prevent excessive movement of the gimbal that would otherwise plastically deform the gimbal. However, if the shock load is substantial, the limiter may be twisted out of engagement with the load beam, and plastic deformation of the gimbal may result. In addition, once the limiter is disengaged, the limiter may interfere with proper orientation of the gimbal when the shock load is removed.
Accordingly there is a need for a shock limiting device in a disc drive that does not disengage the gimbal under any anticipated shock load condition.
Against this backdrop the present invention has been developed. The present invention is a suspension limiter that positively engages or interlocks with a feature of the load beam supporting the gimbal, or vice versa, that in turn supports the read/write transducer to preclude disengagement of the limiter during a shock event. One embodiment of the suspension limiter in accordance with the present invention has a cantilevered arm extending from the gimbal that extends over a portion of the load beam. The distal end of the cantilevered arm has a hook shape and a tip adapted to interlockingly engage an aperture in the portion of the load beam directly beneath the hooked end of the arm. Other embodiments have a hooked tab that interlockingly engages an aperture either in the gimbal or the load beam to interfere with and thus prevent the tab from disengaging the gimbal from the load beam thus limiting the travel of the head and gimbal away from the load beam when excessive shock loads are applied to the drive. These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings.